- AIts radius decreases.
- BIts radius increases.
- CThe bubble collapses.
- DNone of these.
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If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be
|
(a) Only inside the pipe |
(b) Only outside the pipe |
|
(c) Neither inside nor outside the pipe |
(d) Both inside and outside the pipe |
When an inert gas is filled in the place vacuum in a photo cell, then
|
(a) Photo-electric current is decreased |
|
(b) Photo-electric current is increased |
|
(c) Photo-electric current remains the same |
|
(d) Decrease or increase in photo-electric current does not depend upon the gas filled |
The direction of the null points is on the equatorial line of a bar magnet, when the north pole of the magnet is pointing
|
(a) North |
(b) South |
(c) East |
(d) West |
An aeroplane in which the distance between the tips of wings is 50 m is flying horizontally with a speed of 360 km/hr over a place where the vertical components of earth magnetic field is 2.0
. The potential difference between the tips of wings would be
|
(a) 0.1 V |
(b) 1.0 V |
(c) 0.2 V |
(d) 0.01 V |
Substance on the choroid is
|
(a) Japan black |
(b) Nigrim pigment |
(c) Carbon black |
(d) Platinum black |
In Young's double slit experiment, the slits are 0.5 mm apart and interference pattern is observed on a screen placed at a distance of 1.0 m from the plane containing the slits. If wavelength of the incident light is 6000 Å, then the separation between the third bright fringe and the central maxima is
|
(a) 4.0 mm |
(b) 3.5 mm |
(c) 3.0 mm |
(d) 2.5 mm |
A charged particle is moving with velocity v in a magnetic field of induction B. The force on the particle will be maximum when
|
(a) v and B are in the same direction |
(b) v and B are in opposite directions |
|
(c) v and B are perpendicular |
(d) v and B are at an angle of 45° |
Silicon is a semiconductor. If a small amount of As is added to it, then its electrical conductivity
|
(a) Decreases |
(b) Increases |
(c) Remains unchanged |
(d) Becomes zero |